The present invention relates to the repair of heart valves, and, more particularly, to methods and apparatuses for the repair of heart valves by fastening the valve leaflets together at their coapting edges.
In vertebrate animals, the heart is a hollow muscular organ having four pumping chambers: the left and right atria and the left and right ventricles, each provided with its own one-way outflow valve. The natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid and pulmonary valves. The valves separate the chambers of the heart, and are each mounted in an annulus therebetween. The annuluses comprise dense fibrous rings attached either directly or indirectly to the atrial and ventricular muscle fibers. The leaflets are flexible collagenous structures that are attached to and extend inward from the annuluses to meet at coapting edges. The aortic and tricuspid valves have three leaflets, while the mitral and pulmonary valves have two.
Various problems can develop with heart valves, for a number of clinical reasons. Stenosis in heart valves is a condition in which the valves do not open properly. Insufficiency is a condition which a valve does not close properly. Repair or replacement of the aortic or mitral valves are most common because they reside in the left side of the heart where pressures and stresses are the greatest. In a valve replacement operation, the damaged leaflets are excised and the annulus sculpted to receive a replacement prosthetic valve.
In many patients who suffer from valve dysfunction, surgical repair (i.e., xe2x80x9cvalvuloplastyxe2x80x9d) is a desirable alternative to valve replacement. Remodeling of the valve annulus (i.e., xe2x80x9cannuloplastyxe2x80x9d) is central to many reconstructive valvuloplasty procedures. Remodeling of the valve annulus is typically accomplished by implantation of a prosthetic ring (i.e. xe2x80x9cannuloplasty ringxe2x80x9d) to stabilize the annulus and to correct or prevent valvular insufficiency that may result from a dysfunction of the valve annulus. Annuloplasty rings are typically constructed of a resilient core covered with a fabric sewing ring. Annuloplasty procedures are performed not only to repair damaged or diseased annuli, but also in conjunction with other procedures, such as leaflet repair.
Mitral valve regurgitation is caused by dysfunction of the mitral valve structure, or direct injury to the mitral valve leaflets. A less than perfect understanding of the disease process leading to mitral valve regurgitation complicates selection of the appropriate repair technique. Though implantation of an annuloplasty ring, typically around the posterior aspect of the mitral valve, has proven successful in a number of cases, shaping the surrounding annulus does not always lead to optimum coaptation of the leaflets.
More recently, a technique known as a xe2x80x9cbow-tiexe2x80x9d repair has been advocated. The bow-tie technique involves suturing the anterior and posterior leaflets together in the middle, causing blood to flow through the two side openings thus formed. This process was originally developed by Dr. Ottavio Alfieri, and involved placing the patient on extracorporeal bypass in order to access and suture the mitral valve leaflets.
A method for performing the bow-tie technique without the need for bypass has been proposed by Dr. Mehmet Oz, of Columbia University. The method and a device for performing the method are disclosed in PCT publication WO 99/00059, dated Jan. 7, 1999. In one embodiment, the device consists of a forceps-like grasper device that can be passed through a sealed aperture in the apex of the left ventricle. The two mitral valve leaflets meet and curve into the left ventricular cavity at their mating edges, and are thus easy to grasp from inside the ventricle. The mating leaflet edges are grasped from the ventricular side and held together, and various devices such as staples are utilized to fasten them together. The teeth of the grasper device are linearly slidable with respect to one another so as to align the mitral valve leaflets prior to fastening. As the procedure is done on a beating heart, and the pressures and motions within the left ventricle are severe, the procedure is thus rendered fairly skill-intensive.
There is presently a need for an improved means for performing the bow-tie technique of mitral valve repair.
The present invention provides a number of devices and methods for fastening or xe2x80x9capproximatingxe2x80x9d tissue pieces together. The term xe2x80x9ctissue piecesxe2x80x9d is to be understood to mean discrete pieces that may be straight, curved, tubular, etc., so long as the pieces are initially disconnected. For example, many of the embodiments of the invention disclosed herein are especially useful for joining two leaflets of a heart valve. The coapting edges of the leaflets thus constitute the xe2x80x9ctissue pieces.xe2x80x9d In other contexts, the invention can be used to anastomose two vessels, either end-to-end, in a T-junction, or otherwise. In these cases, the two vessels define the xe2x80x9ctissue pieces.xe2x80x9d One specific application of using the invention to perform an anastomosis is in a coronary artery bypass graft (CABG) procedure. Another example of an application of the present invention is in wound closure, wherein the facing edges of the wound are joined. In sum, the present invention in its broadest sense should not be construed to be limited to any particular tissue pieces, although particular examples may be shown and disclosed.
The present invention includes a number of devices and method for both stabilizing the tissue pieces to be joined, and fastening them together. Some embodiments disclose only the stabilizing function, others only the fastening function, and still other show combination stabilizing and fastening devices. It should be understood that certain of the stabilizing devices can be used with certain of the fastening devices, even though they are not explicitly shown in joint operation. In other words, based on the explanation of the particular device, one of skill in the art should have little trouble combining the features of certain of two such devices. Therefore, it should be understood that many of the stabilizing and fastening devices are interchangeable, and the invention covers all permutations thereof.
Furthermore, many of the fastening devices disclosed herein can be deployed separately from many of the stabilizing devices, and the two can therefore be deployed in parallel. Alternatively, and desirably, however, the fastening and stabilizing functions are performed with one device.
The stabilizing and fastening devices of the present invention can be utilized in either standard open surgical procedures, endoscopic procedures, or percutaneous procedures. In one embodiment the devices can be delivered through an open chest either transapically or transatrially. In another embodiment, the stabilizing and fastening devices can be introduced through an incision performed over the roof of the left atrium. In yet another embodiment the devices can be delivered into the left ventricle through the right chest via a thorascope. The devices can also be delivered percutaneously, via a catheter or catheters, into the patient""s arterial system (e.g. through the femoral or brachial arteries). Other objects, features, and advantages of the present invention will become apparent from a consideration of the following detailed description.